1. Field of the Invention
The present invention relates to the field of flat panel displaying, and in particular to an organic electroluminescence device and a manufacturing method thereof.
2. The Related Arts
A flat display device has various advantages, such as thin device body, low power consumption, and being free of radiation, and is thus of wide applications. The flat display devices that are currently available include liquid crystal displays (LCDs) and organic electroluminescence devices (OELDs), which are also referred to as organic light emitting diodes (OLEDs).
The known liquid crystal displays are generally backlighting liquid crystal displays, which include an enclosure, a liquid crystal display panel arranged in the enclosure, and a backlight module mounted inside the enclosure. The principle of operation of the liquid crystal display panel is that liquid crystal molecules are interposed between two parallel glass substrates and a driving voltage is applied to the glass substrates to control the rotation of the liquid crystal molecules so as to refract out the light from the backlight module to form an image.
Referring to FIG. 1, the conventional liquid crystal display panel generally comprises: a thin-film transistor (TFT) substrate 302, a color filter (CF) substrate 304 that is laminated on the thin-film transistor substrate 302, and a liquid crystal layer 306 arranged between the thin-film transistor substrate 302 and the color filter substrate 304. The thin-film transistor substrate 302 drives the liquid crystal molecules contained in the liquid crystal layer 306 to rotate in order to display a corresponding image.
The organic electroluminescence devices, which show the characteristics of self-illumination, high brightness, wide view angle, high contrast, flexibility, and low energy consumption, attract wide attention for serving as the next-generation display measures and gradually substitute the conventional liquid crystal displays for wide applications in various fields including mobile phone screens, computer monitors, and full-color television. The organic electroluminescence devices are different from the conventional liquid crystal displays in that they need no backlight and they use extremely thin coating layers of organic materials directly formed on the glass substrates so that when electrical currents flow therethrough, the organic material coating layers emit light.
The currently available organic electroluminescence devices are classified according to the driving methods used and include passive-matrix organic light emitting diodes (PMOLEDs) and active-matrix organic light emitting diodes (AMOLEDs). Referring to FIG. 2, the AMOLED generally comprises a substrate 502, a thin-film transistor 504 formed on the substrate 502, and an organic light-emitting diode 506 formed on the thin-film transistor 504. The thin-film transistor 504 drives the organic light-emitting diode 506 to give off light in order to display a corresponding image.
The conventional ways of activation are generally high temperature activation and laser activation. When the high temperature activation is employed, due to the presence of a PI (Polyimide) layer, the activation temperature is not allowed to exceed 400° C. However, if the temperature is lower than 400° C., insufficiency of activation may result, leading to deterioration of the OLED thin-film transistor substrate. When laser activation is employed, irradiation of the laser to the PI layer causes property change of the PI layer due to absorption of the laser, leading to lowering of the yield rate of the OLED thin-film transistor substrate and increasing of the manufacturing cost.